U.S. Pat. No. 1,896,425 (to Scarfi) discloses an envelope which may be sealed several times in a successive manner so that the envelope may be used several times for mailing purposes, and is provided with means for separating the closure flap from the body of the envelope so that no tools or letter-openers are required in the opening operation. The envelope includes a closure flap comprising two strips, a main closure strip, which has its obverse surface treated with glue, and an auxiliary closure flap continuing therefrom. The auxiliary flap is folded over to lie flat upon the main flap but does not adhere to the glued surface of the latter. Basically, the Scarfi envelope provides a plurality of closure flaps wherein a top closure flap has an upper gummed surface which is the first flap used to originally seal the envelope. A string is used to separate the auxiliary flap from the main closure flap, thereby opening the envelope. For a second or successive use of the envelope, the gummed surface of the main flap is caused to adhere to the body of the envelope, and the envelope is opened a second time by pulling the second string.
While the envelope disclosed by Scarfi provides for successive or multiple uses, there are some unaddressed problems. There is no disclosure of a security mechanism or tamper-evidencing feature for ensuring that contents are received by the intended recipient. The gummed or glue-treated surfaces of the envelope are unprotected prior to activation or use. This can lead to unwanted activation, deterioration or contamination of the glue-treated or gummed surface. A related problem is that because the gummed surfaces are unprotected, the overlaid auxiliary and main flaps may become stuck together rendering the envelope inoperative for its intended purpose. The ends of the opening strings of the Scarfi envelope project from the edges of the envelope and this can damage automatic handling equipment or cause premature tearing of the envelope itself.
U.S. Pat. No. 2,859,907 (to McFarland), particularly FIGS. 10-13 thereof, discloses an envelope including a sealing and opening tape with a protective layer or release coating on at least one side. U.S. Pat. Nos. 211,725 (to Foster), 754,201 (to Davalos) and British Patent 16,784 (to Cooper) disclose envelopes with tearing strips formed by one or more lines of weakness. However, there is no disclosure or suggestion in these patents about how to achieve an envelope for more than one successive use, nor is there any suggestion about providing a dedicated, tamper-evidencing security feature for a multiple use envelope.
Although the envelopes disclosed in the above-noted patents and commercially available envelopes, particularly air express envelopes such as those used by "Federal Express".RTM., represent improvements in the art, if such envelopes could be used securely more than once, i.e., by successive senders and recipients, expensive natural resources could be saved. Additionally, it would be advantageous if such multi-use envelopes could be converted practically and easily to another use after being used by more than one sender and recipient, saving additional money and resources.
Clearly with current envelope technology, efficiency, security and conservation are not optimized. Accordingly, there is a need for a durable, cost efficient, secure multiple-use envelope.